Generally, a light emitting diode (LED) is capable of implementing high brightness with low power and is widely used for lighting and the like. The light emitting diode is operated by direct voltage. When an external power source supplies alternating voltage, the alternating voltage is converted into direct voltage to generate driving voltage for driving the light emitting diode.
A general light emitting diode has a structure wherein an N-GaN layer, an active layer and a P-GaN layer are sequentially formed on a sapphire growth substrate, and includes a p-electrode formed on the P-GaN layer, an n-electrode formed on the N-GaN layer, and, optionally, a buffer layer formed between the sapphire growth substrate and the N-GaN layer to relieve lattice mismatch and a difference in coefficients of thermal expansion therebetween.